Retinal vascular leakage is an important mechanism of visual loss in ocular inflammatory disease. The presumed site of retinal vascular leakage is the retinal capillaries, which are composed of pericytes and endothelial cells. It is likely that immune- mediated disease alters pericyte or endothelial function in a manner that produces vascular leakage. This project is concerned with quantifying the specific mediators that are involved in producing these changes so that more appropriate therapy can be targeted.